Polyplacocystis symmetrica (Penard, 1904)

Diagnosis: Protoplast 14-25 µm in diameter; scales 3.8-11.0 µm long and 2.4-3.1 µm broad; scales delicate, slightly curved, oval and very different in size; every scale with a reticulate surface structure, surrounded by a thick, hollow marginal rim; scales usually symmetrically organized around the base of the axopodia, thus forming a tube; axopodia very long, up to three times the cell diameter; 2-4 contractile vacuoles, often bulging.

Ecology: In different water types, mostly in clear waters, sometimes in sediments; also in dystroph water. Switzerland, Germany, The Netherlands, Canada, Australia.

Remarks: The tubular organized scales around the axopods are very characteristic in light microscopical view.

Polyplacocystis symmetrica - Ferry Siemensma
Polyplacocystis symmetrica, body 18 arrows indicate oval scales.
Polyplacocystis symmetrica - Ferry Siemensma
Polyplacocystis symmetrica, characteristic shape
Polyplacocystis symmetrica
Dried periplast, with some scales visible
Polyplacocystis symmetrica, with Drepanomonas as prey.
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